In a hybrid vehicle, electric vehicle, fuel cell vehicle, etc., an electrical apparatus such as an inverter is operated with electrical power from a high-voltage power supply to thereby run the vehicle, and therefore, if the vehicle receives a severe impact caused by a collision, etc., and if the level of the impact exceeds the breaking strength of the electrical apparatus, the apparatus may be damaged, and depending on the degree of damage of its electrical system, high-voltage electrical power may be leaked. In order to prevent such a situation, it is necessary to immediately detect a vehicle collision, cut off power supply from a power source at the time of the collision, and immediately discharge electric charge accumulated in a high-voltage capacitor.
The below-listed Patent Document 1 discloses a structure in which a conductive film is extended throughout the inner surface of a lid of a case containing an inverter, and the conductive film is electrically disconnected when the lid is deformed. An ECU detects a current value I flowing through the conductive film and judges whether the current value I is approximately zero or not. Then, if it is approximately zero, the ECU judges that the inverter has received an impact and turns off a system main relay, in order to cut off power supply from a running battery. The ECU also stops the inverter so as to put a motor-generator into an inactive state where it cannot generate electrical power.